Passenger seats on common carriers (such as buses, trains, ships, and aircraft) often utilize arm rests, which are pivotally mounted to the passengers seats. The arm rests may be rotated aft into a substantially vertical (or stowed) positions, and rotated forward into substantially horizontal (or deployed) positions.
The height and angle of the deployed positions of the arm rests are typically adjusted by a positional cam mounted to a portion of the passenger seat frame or spreader, and a rigid pin mounted to the arm rest proximate the pivotal coupling point.
In the deployed position, the arm rest's pin rests directly on the positional cam, which supports the load from the arm rest itself, as well as a load exerted by a passenger seated in the passenger seat when the passenger utilizes the arm rest for support.
In these conventional designs, the rotation of the arm rest into the deployed position creates a pinch point between the pin and the cam. This pinch point poses a safety risk because a passenger could potentially insert his or her hands or other appendages between the positional cam and the pin, thereby risking bodily harm when the load from the arm rest and/or passenger is applied to the passenger's hand or other appendage.
In an effort to eliminate these potential risks, a close-out shroud is often added to prevent access to such cavities or voids, as illustrated in FIGS. 4A-4B and 5A-5C. As a result, the close-out shroud prevent passengers from being able to put any part of their body between the cam and the pin. These close-out shrouds are typically formed as a single piece of flexible plastic material, in which an upper portion of the close-out shroud travels with the arm rest and a lower portion remains fixed to the seat frame. As a result, the elastic properties of the plastic material allow the transition area of the close-out shroud that is positioned over the actual pivot location/pinch point to bend with when the arm rest is deployed and to straighten when the arm rest is stowed.
The choice of approved materials for these close-out shrouds have limited the options for creating close-out shrouds that can withstand the repeated use without failure. For example, federal aviation flame resistance requirements of 14 CFR 25.853 (a) (AMEND 25-83) require the use of flame retardant plastic materials, which are defined as materials that shall self-extinguish once ignited during vertical burn testing. Conventionally available flame retardant material choices typically have lower elasticity (i.e. are more brittle) and therefore are not robust enough to withstand the frequency with which the arm rests are raised and lowered over time. As a result, these conventional close-out shrouds often break after repeated use, which creates another potential safety hazard after the close-out shroud has broken and failed. For example, polycarbonate (a known flame retardant plastic material commonly used in aircraft seats) has been tried as a close-out shroud and failed due to its lack of fatigue resistance.
It is therefore desirable to develop a close-out shroud that will block access to cavities or voids formed by articulating components, while also having increased durability through additional engineering features and/or flame retardant material improvements so that that the close-out shroud is able to flexibly adapt its shape to meet specific mechanical motions over a greater number of cycles without breaking.